Schematic Reference: Exterior Lights Schematics

Did you review the backup lamp operation and perform the necessary inspections?

Go to Step 2

Go to Exterior Lighting Systems Description and Operation

1. Block the wheels or set the park brake.
2. Turn ON the ignition, with the engine OFF.
3. Press the brake pedal.
4. Place the transmission in REVERSE.

Do both backup lamps illuminate?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

Is only one lamp inoperative?

Go to Step 4

Go to Step 6

Test the backup lamp supply voltage circuit of the inoperative lamp for high resistance, an open, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 5

Test the ground circuit of the inoperative lamp for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 11

Test the ignition 1 voltage circuit of the park/neutral position switch or back up switch for high resistance, an open, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 7

Test the backup lamp supply voltage circuit of the park/neutral position switch or back up switch for high resistance, an open, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 8

Test the ground circuit of the lamps for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 9

Does the vehicle have an automatic transmission?

Go to Step 10

Go to Step 12

Test the park neutral switch adjustment and if necessary, adjust to specification. Refer to Park/Neutral Position Switch Adjustment in Automatic Transmission - 4L80-E.

Did you find and correct the condition?

Go to Step 15

Go to Step 12

Inspect for poor connections at the harness connector of the inoperative lamp. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 13

Inspect for poor connections at the harness connector of the park/neutral position switch or back up switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 14

Replace the inoperative lamp. Refer to Tail/Turn Signal Lamp Replacement .

Did you complete the replacement?

Go to Step 15

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Replace the park/neutral position switch or back up switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transmission - 4L80-E, or Backup Lamp Switch Replacement in Manual Transmission - NV 4500.

Did you complete the replacement?

Go to Step 15

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3